What are the OpenGL settings on the Pro version? Having Use Max Texture Size ticked on kills SU performance on large models.

Drop Vertices by Tig must also works and advantage you can flat on any objects, Z, etc...

No-not the eneroth...the native one. for some reason it was not showing up...now it is...go figure...

If you do a Google image search "roof" you will find some large photos. Too correct them and make them seamless in Photoshop: Filter/Lens Correction...to get shingles to lie flat Filter/Other/Offset...to create the horizontal and vertical seams Burn or Dodge....to expose the image evenly (flatten) so that shadow/light/dirt are not creating a pattern. There are other ways to flatten...i.e. You can "radial fill" towards the sun source with an opaque mask to reduce shadow. Take a neutral sample from the image. (this is a bit advanced and needs a bit of practice.) After a few tries it is quick solution to make your own and you never need to waste time looking again.

What textures/materials do you have in the model? Maybe there is a color lookup change happening between the PDF and jpg that is making some material look more yellow? To answer your second question, no, jpg does not always look good to me. In particular, unless I have profiles set to 1 they come out very heavy in the jpg. Like Dave, unless I know the recipient can only handle jpg, I prefer png, uncompressed tiff, or PDF.

Yes group the retaining wall entities. You might use "Tools on Surface" plugin to draw your profile on the group, but not necessary. The group should not affect the SB from contours process. I like to make curves of the contours with recurve rb. The process will also assure you've got a continuous set of segments for each contour. You can also use simplify curve routines (Fredo Tools?). But definitely look at Toposhaper that resolves some these requirements. There should definitely only be the single contour set, not a flat surface or second set below. To raise the contours from a flat set, there are various methods, You might make a vertical array of edges or guides to snap to your intervals. I think the push-pull method is more trouble. Look for Daniel Tal's 2008 lecture video too. You will see more on SB work. https://sites.google.com/site/3dbasecamp2008/